In wireless communication networks, a frequency spectrum may be shared between different network devices. The network devices may be in particular devices with cognitive radio function. Such a device may be a device that automatically changes its transmission or reception parameters, in a way in that the entire wireless communication network communicates efficiently, while avoiding interference with licensed or licensed exempt users. This alteration of parameters is based on the active monitoring of several factors in the external and internal radio environment, such as radio frequency spectrum, user behavior and network state.
In such wireless communication systems, for example with 3GPP LTE-advanced devices with cognitive radio function, the frequency spectrum, or moreover frequency bands of the spectrum may be licensed according to a license scheme. In particular, the scheme may be related to a service (QoS, quality of service) guarantee scheme, as provided by the Authorised Shared Access (ASA) concept in cognitive radio technology. The Authorized Shared Access (ASA) is a complementary spectrum authorization scheme for commercial use that may enable timely availability of harmonized spectrum for mobile broadband while ensuring predictable QoS for all rights holders. ASA may allow new users to access to an already licensed spectrum with the obligation to protect the incumbent user. For example it may an IMT service to access the bands that are under-utilised by existing primary uses, especially to bands that have been allocated to mobile but not made available for mobile use through current regulatory means. The access may be regulated via cognitive radio capabilities, i.e. geolocation databases complemented, if required, by sensing. ASA is neither exclusive licensing nor license-exempt but has few commonalties with licensing-light. The incumbent user works on a primary basis maintaining its spectrum assignment over time in line with the National Table of Frequency Allocation. ASA allows selected authorised users to share the ASA band under some technical condition. Predictable QoS can be ensured for those limited number of non-overlapping authorised users.
The actual ASA concept is a framework to share a spectrum between limited numbers of authorized users. Under this concept, the initial user(s) (e.g. the “incumbent(s)”) would share its spectrum with one or several new users (the “incoming user(s)”) in accordance with a set of conditions defined by the regulation. These conditions may be “static” (e.g. exclusion zone, restricted time for operation) or more ‘dynamic’ (e.g. geographic/time sharing, on-demand authorization of operators).
However, there may be a need for an improved system and method being able to ensure a predictable quality of service (QoS) for all spectrum users.